Forget flourless this and molten that. When was the last time you had good old, plain old chocolate cake? If it was at somebody’s 12th-birthday party, you’re in for a surprise. Now that Petit Robert Bistro has introduced its signature dessert, Gâteau Petit Robert, grown-ups can reclaim the joys of a classic. The Grand Marnier–soaked génoise is dense as a brownie but not overly sweet; it’s frosted with bittersweet-chocolate ganache but isn’t lost in its frosting, or in its light sprinkling of white-chocolate shavings. In short, this version is streamlined, refined — a fitting ending to a meal of, say, escargots bourguignon and lapin moutarde. And yet your inner kiddie won’t feel totally out of place: garnishing the plate is a four-inch replica of the Eiffel Tower, made entirely of chocolate. It’s like a toy for your sweet tooth to play with.

Available for $7 at Petit Robert Bistro, 468 Comm Ave, in Boston. Call 617.375.0699.